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J. M. MOOLELLAN. BRUSH HOLDER FOR DYNAMOS.

No. 409,646. Patented Aug. 20, 1889. 1 10.1.-

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35 the dynamo.

UNITED STATES PATENT OFFICE.

JAMES M. MCOLELLAN, OF ST. PAUL, MINNESOTA, ASSIGNOR TO GEORGE II. FINNAND JOHN E. MUN SON, OF SAME PLACE.

BRUSH-HOLDER FOR DYNAMOS.

SPECIFICATION forming part of Letters Patent No. 409,646, dated August20, 1889.

Application filed March 20, 1889. Serial No. 304,043. (No model.)

useful Iin in'ovements in Electric Brush-Holders, of which the followingis a specification.

My invention relates to the brush-holders of electric motors anddynamo-electric machines; and it consists generally in the constructionand combination hereinafter described, and

particularly pointed out in the claim.

\Vith the ordinarybrush-holderof the class described scarcely one-halfof the brush can be utilized. After the ends are worn off the remainderof the brush becomes useless eX- cept for scrap-copper.

It is the object of my invention to provide means for moving andadjusting the brush, so that it can be advanced forward or its positionchanged, so as to utilize nearly all of.

the brush. I do this by providing an auxiliary brush-holder, which isadapted to be detachably and adjustably secured in the ordinarybruslrholder, the brush being secured in the auxiliary holder and asworn down moved forward or readjusted in the manner hereinafterdescribed, by which means fully seven-eighths of the brush is utilized,thus making a great savin g in the cost of renew- 0 ing the brushes.

In the drawings forming part of this specification, Figure 1. is a sideelevation of my auxiliary brush-holder, showing the manner of securingitin the ordinary brush-holder of Fig. 2 is a plan view; Fig. 3, alongitudinal section on line of Fig. 2, and Fig. 4 a cross-section onthe line y y of Fig. 2.

In the drawings, A represents the ordinary bruslrholder of a dynamo,which is secured to the dynamo in the usual manner.

secured therein in any desired position by means of the set-screw 9, orto be entirely removed from it. This shank may be made hollow, as shownin Fig. 3, to lessen its cost, or solid to increase its conductivity.

The head 11 of the auxiliary holder is cored or hollowed out to receivethe brush 17 and to allow both lateral and vertical play of the brush inits socket. The brush is firmly secured in the desired position in thehead by means of the set-screw 13 carrying or pressing upon the plate15, which is adapted to rest upon the brush as the set-screw is drivendown upon it. The brush is preferably constructed of thin strips ofsheet-copper, though other forms of brushes may be used.

The mode of operation is as follows: The brush is placed in the head 11and secured in suitable position by setting the screw 13 down upon theplate 15. The shank 5 is then inserted into the sleeve 7 and secured bythe screw 9 being adjusted so as to bring the brush 17 into properposition for use. As the brush is worn away by use it can be advanced bysliding the shank 5 in the sleeve 7 until the brush is worn down to thehead 11.

I claim as my invention The combination, with the brush-holder, of adynamo-electric machine having the sleeve 7 and set-screw 9, of anauxiliarybrush-holder I having the shank 5 slidably adjustable in saidsleeve, and the head 11, suitably recessed to receive the brush 17 andprovided with the set-screw 13 and the plate 15, by means of which thebrush is secured in said "head, combined and operating si'ibstantiallyas described.

In testimony whereof I have hereunto set my hand this 6th day of March,1885).

JAMES M. MCCLELLAN.

In presence of ARTHUR P. Lo'rnEoP, T. D. MERwnv.

